The problem with this one is that + sentence ( A buaithlakna / A that lohna chu...)
Entirna:
English - The problem with this one is that he is not interested in English.
Mizo - A buaithlakna chu (he pa hian) English hi a ngaihsak...

You are supposed to + Verb (... tura beisei / ngaihruat i ni.)
Entirna:
English - You are supposed to avoid that flirtatious girl.
Mizo - Kha nula par-tin-lawr-lepler-i kha hnawmhnawih lo tura rin i ni.
English – You are supposed to agree...